1. Field of the Invention.
This invention relates to sulfonate-containing bis-maleimide resins. More particularly, this relates to sulfonate containing bis-maleimides prepared by reacting an aromatic disulfonyl chloride and m- or p-hydroxy phenyl maleimide in an organic solvent in the presence of a base. These bis-maleimide resins can be used in the production of fiber or fabric reinforced composites or laminates.
2. Description of the Prior Art.
High performance composites can be made by embedding various types of fibers or fabrics in a resin matrix. The matrix resins usually employed are an epoxy, phenolic, polyester and poly(sulfones). In addition to these resins, bis-maleimides have also been used to develop high performance composites with fibers or fabrics such as carbon, graphite and glass for certain applications. Besides high reactivity, bis-maleimides undergo addition type polymerization reactions producing networks without any volatile by-products. Accordingly, void-free composite materials for high temperature applications can be easily fabricated from these bis-maleimides.
Bis-maleimides containing groups like sulfone, ether, methylene, isopropylene, sulfide, etc., in the main chain are documented and known for thermal stability. Similarly, polymers containing sulfonate linkages show thermal stability and process ability. Though thermally stable co-poly (ester-sulfonates) with good mechanical properties are known, bis-maleimides containing sulfonate linkages are not known. So, bis-maleimides containing sulfonate groups would be expected to yield the combining properties of thermal stability and processability.
The primary object of the present invention is to develop new sulfonate containing bis-maleimides that can be used as a matrix resin for the fabrication of glass, graphite or carbon fiber or cloth composites and adhesives.